Brunello Cucinelli, the 59-year-old founder of the luxury fashion house that bears his name, has become a billionaire.

Knitwear brand Brunello Cucinelli SpA has more than doubled in value since its initial public offering in Milan last April, giving Cucinell a net worth of at least $1bn, according to the Bloomberg Billionaires Index. He has never appeared on an international wealth ranking.

'From the beginning we hoped for a positive and gentle listing', Cucinelli said by phone from his Milan showroom through a translator. 'Investors appreciate our quality, our positioning in the absolute luxury market and our Italian heritage'.

The Solomeo, Italy-based company, which sells $4,530 suede jackets and $1,920 cashmere cardigans, had sales of $360 million in 2012, up 15.6% in a year.

Cucinelli’s 63% stake in the business is valued at $947m. He collected more than $90m selling shares in the IPO.